<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue@2.6.14/dist/vue.js"></script>
</head>
<body>
    <div id="app">
        <input type="text" v-model="keyword" @keyup.enter="handleEnter">
        <p v-for="item of history">{{item}}</p>
    </div>
    <script>
        new Vue({
            el:"#app",
            data:{
                keyword:"",
                history:[]
            },
            methods: {
                handleEnter(){
                    // console.log(this.keyword);
                    if(!this.history.includes(this.keyword)){
                        this.history.unshift(this.keyword)
                    }else{
                        console.log(this.keyword);
                        var index = this.keyword.indexOf(this.history);
                        this.history.splice(index,1)
                        this.history.unshift(this.keyword)
                    }
                    this.keyword = ""
                }
            },
        })
    </script>
</body>
</html>